Eichornia crassipes

Water hyacinth

Family: Pontederiaceae

Origin: South America

Close up of Water Hyacinth flowers.
Leaves are distinctive in shape with curled edges and bright green in colour. Water hyacinth flowers are pale purple in colour with dark purple markings.
Photo credit: Annie Lamb, Department of Primary Industries, Victoria, Australia

Regional Pest Management Plan (RPMP) status

  • National Pest Plant Accord Species
  • Notifiable organism

View more about the RPMP statuses

General description

Perennial free-floating, mat-forming, stoloniferous aquatic herb. Roots are dark, feathery and < 2.5 m long. Leaves are bright green, rounded and shiny, with bulbous bladder-like leafstalks when young. Flowers are pale purple with darker purple/blue markings and a yellow spot and are borne in clusters above the leaves in mid-summer – early autumn.

What you need to know

To help protect our environment:

  • You must not breed, distribute, release or sell water hyacinth. As water hyacinth is a National Pest Plant Accord species, these restrictions apply within the Auckland region and across the whole of New Zealand.

If you see water hyacinth anywhere, you must report it to the Ministry of Primary Industries on 0800 80 99 66.


Still and slow-flowing water bodies, lakes, rivers, ponds, streams.


Seeds dispersed by water and possibly waterfowl and other animals. Vegetative spread from stolons and budding, dispersed by water and wind. Human-mediated dispersal through deliberate plantings and movement of contaminated boats and equipment.

Impact on environment

Forms dense mats, outcompeting native plants and altering habitat structure. Clogs waterways, impeding drainage and recreational activities.


Recommended approaches

Do not attempt to undertake control of this species. The Ministry of Primary Industries will carry out the control of this species.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Water Hyacinth floating on surface of a pond.
Water hyacinth is a perennial free floating aquatic plant that forms dense mats on the surface of slow moving water bodies. Young leaves have small bladders to help keep them afloat.
Photo credit: Holly Cox